1. Field of the Invention
This invention relates generally to a vibration isolator for a TV camera, which prevents an image blur due to vibrations of the TV camera, and more particularly to a vibration isolator for a TV camera, in which a lens device is attached to a body of the TV camera through a lens supporter.
2. Description of Related Art
To attach a box-shaped heavyweight lens device such as an electronic field production (EFP) lens device to the body of a handy TV camera such as an electronic news-gathering (ENG) camera, a lens supporter is fixed to a tripod first. Then, the body of the TV camera is fixed to one side of the lens supporter, and the lens device is fixed to the other side of the lens supporter. Thus, the weight of the lens device is not directly applied to the body of the TV camera.
Some lens devices have a built-in vibration isolator. The vibration isolator has a correcting lens for correcting an image blur. The correcting lens is moved in such a manner as to correct the image blur according to the direction of the vibration, thus acquiring a satisfactory image which is not blurred.
On the other hand, there has been disclosed an adapter-type vibration lens unit which may be separated from the lens device (Japanese Patent Provisional Publication Nos. 63-201624, 64-33519 and 6-189181).
The conventional lens device which has the built-in vibration isolator, however, is very expensive since the vibration isolator must be incorporated into each lens device. In view of the price, it is preferable to use one vibration isolator for different kinds of lens devices. The above-mentioned three Japanese Patent Provisional Publications, however, disclose neither a method of attaching the lens unit to a lens or a camera nor a means for attaching the lens unit to connecting parts (hook mounts), which are different in shape according to the types of the lens or the camera.
According to the adapter-type vibration lens unit (the intermediate adapter) disclosed by Japanese Patent Provisional Publication No. 6-189181, lens inherent information, which is required for controlling the vibration isolation, is transmitted from the lens device. It is, however, impossible to control the vibration isolation if the lens device with no means for transmitting the information is used.
In view of the foregoing, it is an object of the present invention to provide a vibration isolator for a TV camera, which is attachable to a variety of lens devices regardless of the shape of a hook mount in a lens or a lens supporter, and which makes possible the vibration isolation control even with the use of a lens device which is not provided with a means for transmitting lens inherent information.
To achieve the above-mentioned object, the present invention is directed to a vibration isolator for a TV camera, in which a lens device is attached to a body thereof across a lens supporter, wherein said vibration isolator provided with a correcting lens for correcting an image blur of said TV camera is provided on said lens supporter.
According to the present invention, the vibration isolator is attached to the lens supporter, and the vibration isolator is commonly used for different kinds of lens devices. This eliminates the necessity of providing the lens device with the vibration isolator, thus reducing the cost for manufacturing the lens device.
Preferably, the vibration isolator is an adapter-type vibration isolator detachably attached to the back side of a mount frame of the lens supporter through connecting means. Therefore, the vibration isolator can be attached to the lens supporter regardless of the shapes of the hook mounts of the lens and the lens supporter.
More specifically, the isolator for the TV camera comprises: supporting means for movably supporting the correcting lens within a plane perpendicular to an optical axis; image blur detecting means for detecting an image blur of said TV camera; an arithmetic unit for calculating a correction movement amount for said correcting lens in accordance with information from the image blur detecting means; drive means for moving the correcting lens in such a direction as to correct the image blur in accordance with information from the arithmetic unit; position detecting means for detecting the position of the correcting lens; and control means for feedback-controlling the drive means so that the correcting lens can be moved by the correction movement amount calculated by the arithmetic unit in accordance with the position of the correcting lens detected by the position detecting means.
In one form, said vibration isolator includes amplitude adjusting means for adjusting the amplitude of the correcting lens for each lens device in accordance with lens information transmitted from each lens device. The lens information relates to, for example, the magnification of the lens, the focal length, the extender, the lens code, or the like, which are required for controlling the vibration isolation. The amplitude adjusting means enables the vibration isolator to properly control the vibration isolation by automatically checking the information relating to the attached lens device.
According to the present invention, the vibration isolator includes information input control part for setting lens information in accordance with the operation of a user in the case that the lens device has no means for transmitting its lens information. The user can freely enter or change the lens information through the information input control part. This allows the vibration isolator to properly control the vibration isolation even if it receives no lens information from the lens device.
In accordance with an alternate embodiment of the present invention, said vibration isolator includes a remote control part provided with a vibration isolation ON/OFF control means for determining whether to operate a vibration isolating function of said vibration isolator and/or a sensitivity adjustment control means for adjusting the sensitivity of the image detecting means for detecting the image blur of said TV camera. Therefore, the cameraman can easily select the ON/OFF of the vibrating function and adjust the sensitivity by operating the remote control part at hand. In addition, the vibrations due to the operation are not transmitted to the lens device.